Maternal smoking during pregnancy has been linked to numerous adverse health outcomes in infancy and longer-term neurobehavioral outcomes. Relatively little attention, however, has focused on effects of prenatal smoking on offspring neurobehavior during the newborn and fetal periods. One key unanswered question is whether exposure to prenatal smoking induces neurobehavioral symptoms of withdrawal/abstinence in newborns. Short-term abstinence in adult regular smokers clearly results in symptoms of withdrawal. Furthermore, evidence from our group suggests alterations in neurobehavior consistent with signs of abstinence in smoking-exposed newborns, effects not evident at 10-30 days. However, although essential for resolving the question of withdrawal in infants, no studies have included intensive measurement of neurobehavior including signs of abstinence over the first month of life. Further, no previous studies of early neurobehavior in smoking-exposed infants have included physiologicalmeasures and measures of fetal neurobehavior. In the proposed study, we will conduct an intensive, short-term, longitudinal study of neurobehavior including signs of abstinence during the newborn and fetal periods in offspring continuously exposed and unexposed to prenatal smoking. Signs of abstinence will be assessed in the context of acomprehensive neurobehavioral examination and measures of newborn nicotine and cotinine levels. The proposed study includes one fetal neurobehavioral assessment during third trimester, followed by eight infant neurobehavioral assessments on days 0, 1,2, 3, 5, 7, 10, and 30 of life. Aims include a characterization of infant signs of abstinence and neurobehavior, dose response relations between prenatal smoking exposure and neurobehavor, physiological correlates of abstinence, and fetal signs of abstinence and neurobehavior. The proposed study will allow us to identify potential signs of abstinence in smoking exposed infants and fetuses and to differentiate immediate versus more persistent neurobehavioral deficits resulting from prenatal smoking exposure. Given that signs of abstinence may interferewith maternal-newborn relationships, results may lead to targeted intervention with newborns and education for parents to improve interactions with exposed newborns. The proposed study may also help to identify infants who may be at risk for the long-term consequences of prenatal smoking, and, potentially might,lead to novel intervention and prevention efforts for pregnant smokers.